Many psychiatric disorders are characterized by dysfunctional impulsivity, defined as "a predisposition toward rapid, unplanned reactions to internal or external stimuli without regard to the negative consequences of these reactions for the individual or others." Dysfunctional impulsivity is multidimensional, consisting of three behavioral components: inability to delay gratification, disinhibition, and distractibility. Mania represents the behavioral extreme of impulsivity as it includes prominent displays of all three of these components. These behaviors often result in dire interpersonal, social and vocational consequences in manic patients. In addition, bipolar disorder frequently co-occurs with substance use disorders, impulsive control disorders, ADHD, and personality disorders, which are characterized by impulsive behaviors. These conditions persist during periods of euthymia in the course of bipolar illness. However, it is unclear whether impulsivity is a core trait of bipolar disorder, occurring during periods of euthymia and depression, or whether it is simply a behavioral syndrome restricted to mania. The objectives of this study are to determine whether the behavioral components of impulsivity persist in bipolar disorder during euthymia and depression using laboratory measures to assess these domains, and to determine whether performance on laboratory tests of impulsivity are associated with "real life" impulsive events and functional outcome. The innovative aspects of this project are the utilization of specific laboratory tests of each behavioral component of impulsivity performed during periods of mania, euthymia and depression in patients prospectively evaluated following an acute manic episode, and the correlation of these laboratory findings with operationalized measures of impulsive life events and functional outcome. Establishing impulsivity as a core trait of bipolar disorder may directly contribute to future efforts to identify treatments to manage this component of the illness, as well as provide models to help better understand the basic neurophysiology of this bipolar disorder. [unreadable] [unreadable]